In an information processing apparatuses such as a personal computer, a basic input-output system (BIOS) is stored in a read-only memory (ROM), and an operating system (OS), application programs, and data are stored in a hard disk. In the information processing apparatus, for starting up the system, the BIOS reads the OS and other facilities from the hard disk to a random access memory (RAM). An application program stored in the RAM is run on the other hand, in an information processing apparatus such as a portable terminal, a BIOS, an OS, application programs, and data are loaded in a ROM from the beginning. In the information processing apparatus, an application program already loaded in the ROM is run to start up the system.
In the information processing apparatus having the OS, application programs, and data stored in the ROM, when the system must be modified, the ROM is replaced with another or the data in the ROM is rewritten by a ROM writer. therein. This leads to an increase in cost. Moreover, the method using a ROM writer requires the special apparatus referred to as a ROM writer.